Evidence of Evolution

This illustration of the three domains of life is like a family tree. The branches that are very far apart are not very similar. Branches that are near each other indicate closely related groups.
Click on image for full size Windows to the Universe original image

What Is Evolution?

Evolution is the process of change through time. Many things evolve. Language
evolves so that English spoken four hundred years ago during the time of playwright
Shakespeare was very different than English spoken today. Technology evolves
over time as new things are invented and modified. Scientific theories evolve
as more data are collected and analyses are done. Life evolves over very long timescales
as species change over many, many generations. This is called biological evolution.
Evolution is the foundation for the modern sciences of paleontology (the study
of fossils and the history of life), ecology (the study of ecosystems), and biology (the study of life)
including medical science.

On a small scale, biological evolution is called microevolution
and involves changes in the occurance of gene types in a population of the
same species over several generations. These changes can lead to changes in
the way a species looks over generations.

On a large scale, biological evolution is called macroevolution
and involves the development of new species through cumulative genetic changes
over many, many generations.

This
Windows to the Universe Exploratour examines the scientific evidence for biological
evolution. Click the “forward” button at the top of this page to continue
the tour and learn more about the scientific basis of evolution.

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